Thermal switch for electric irons



jam, 26 @26 J. N. LEWIS THERMAL SWI TC H FOR ELECTRIC IRONS Filed April29, 1922 ENC., fr @@QPURATON Bln h Application lled April 9,9, Serialt'o.

To aZZ whom t may concern:

Be it known that l, Jixruss N. Lewis, a. citizen of the United States ofAmerica, residing at Detroit, in the county of lfayne and State ofMichigan, .have invented certain new and useful linprovements in'lherinal Switches tor Electric iirons, of which the following is kaspecication, reigerence being had therein to the accompanying drawings.

This invention relates an automatic control device for electric ironsand tlie pri mary object oit my invention is to provide an electric ironwhich will eliminate lires incident to overheated irons being left on anironing board or other combustible supports. lt is a well linown tactthat a large percentage ot' tires occur by the operator or" an ironneglecting to turn oil the current after using 'the iron or whentemporarily leaving the same on an ironing board or other supportsAnother object of my invention is to pron vide a diaphragm controldevice of general application, but especially designed :tor an electriciron, the device utilizing the expansive orce of a medium for flexingtlie diaphragm in one direction, and partial vacuum or the inherentretractive `force on the diaphragm for flexing it in an oppositedirection. As an instance oi' such diaphragm actuating medium may becited a liquid or low beat coeilicicnt and by its volumetricdisplacement cause lexure of the diaphragm.

A further object of this invention is to furnish an iron with adiaphragm control device that will automatically cut on and ofi anelectric current to the iron and tlius prevent waste of current andobviate the necessity of the operator of the iron turning on and oil aswitch each and every time the iron is to be rendered inoperative.

i still further object oi my invention is to rnish iron with a diaphragmcontrol cvice that may be sot at will `for desired -niniinum and maximumtemperatures in connection with the iron. For instance, the control.device may be regulated to shut ofi to the iron at a maximum temperatureand turn on the current at a minimum temperature, thus permitting theoperator 'to set the iron for dii'ierent lrinds Worin stillv furtherobiect of? my i 'to provide an iron witli a switcl leverage mechanismtor switch, the leverage mechanism permit g of the iron bein@- verysensitive to least fluctuation in temperature consequently the controlor the iron may be regulated to a line degree as may be essential inconnection with various kinds of work.

The above are a few of lthe ooccts tained by the simple and durableconstruction to be hereinafter described, and. reisrence will new be had`to the wherein Figure l a horizontal sectional view the iron;

Fig. 2 is a .longitudinal vertical sectional View of the saine, and

Fig. 3 is a cross sectional view talren on the line Tillmll'i of Fig. 2.

n the drawing the reference numeral l denotes an iron body having itsupper :tace provided with a marginal wall 2 and on said base, withinsaid wall, is an electric heating element 3, said element being of theordinarg,T and well known t* pe including a resistance coil and suitableinsulation.

@ver the electric heating element 3 is placed a shield made ofinsulation mate rial, for instance asbestos and this shield hasdepending side walls 5 resting on the iron body l at tbe outer sides oftbe marginal wall 2 so as to cooperate with said wall in electricheating element and thus coni'ine the heat in the lower portion of theiron body, preventing its dissemination in the upper portion ci the ironbody, and consequentlvv a waste ot' the energy supplied to the elecrichealing element.

Extending over the top ot tlie shield 4i 's a spider having longitudinalarms 6 and tr verse arms T, the arms 6 having the outer ends thereofconnected by screws 8 o other fastening means to the marginal wall andthe ends ot the arms 7 extend downwardly at the outer sides of thedepending walls 5 ol' 'the shield el.

Centrally o the spider is a hold tending into an opening l() yin theshield Il, the holder 9 being directly above the electric heatingelement and susceptible to the heated air within the chamber containing'the bea* element. Suite-.bly attached. to holder l) is a hermeticallysealed co or diaphrfim device. 1l susce p ilil plug 12 mounted in saidholder, said plug permitting of the container being filled with mercury,oil or any liquid or material hav.

ing a low coethcient of heat expansion. The device 11 can beconveniently made-ot two circumferentially corrugated ldisks ord1aphragms having flanged edges secured together to form a chamber orhollow member, and with the lower wall of the member held by the holder9 the upper wall or diaphragm of the member may be idexed by volumetricdisplacement or the medium within the member or container.

@n the forwardmost arm 6 of the spider is an upright bearing 13 andpivotally connected to said bearing is the forward end of a lever 14,said lever extending rearwardly over the top of the control device 11.Screwed in the lever 14, coaxially of the control device 11, is aContact member having a head 1G adapted to be engaged by a pad 17centrally of the control device 11. Mounted on the contact member 15 andbearing on the lever 14 is a fingerpiece 18 locked relative to thecontact member 15 by a set screw 19. With the set lscrew 19 loose thefinger piece 18 may be adjusted relative to the Contact member saidContact member may be adjusted in the lever 14. Suchad. justment,however, is limited by either the head 16 contacting with the lower faceof the lever 14 or the finger piece 18 contacting with the upper face ofsaid lever. As the contact member 15 is set in Fig. 2, it may be engagedby the pad 17 and the lever 14 ac.- tuated to operate a switch.

On the forward arm 6 of the spider and on the marginal wall 2 of theiron body 1 are posts 20 provided with detachable nuts 21 employed forpositioning and holding a cover 22 on the iron body. rlhis cover has itsrear wall 23 provided with a housing 24 and fixed in said housing is aninsulator 25 provided with binding posts 26 and contact members 27. Slidble in the insulator 25 is a pin or plunger 8 having a conical head 29held normally in engagement with the contact members 27 byl theexpansive force of a coiled spring 30 encircling thepluvnger 28 withinthe insulator. The upper end of the plunger has a transverse pin 31engaged by the forked or bifurcated end 32 of the lever 14 so that saidlever may raise the plunger 28 against the action of the spring 30 orpermit the expansive `torce of said spring to lower the plunger 28.

The housing 24 supports the usual acks 33 adapted to receive a soc-ketorplug (not shown). One of the jacks 33 is connected by a conductor 34 toone of the binding posts 26 and the other jack is connected by aconductor 35 to the electric heating element hardest' 3, which in turnis connected by a conductor 36 to the binding post 26.

Suitably attached to the .cover 22 is a conventional form of handle 37by which the iron may be manipulated.

It is through the medium ofthe adjustable Contact member 15 and thecontrol device 11 that the iron may be set to turn on the electriccurrent when theiron has cooled, for instance one hundred andtwenty-five degrecs Fahrenheit and turn olf the electric current whenthe iron has heated to the ex*- tent or three hundred and fifty degreesFahrenheit or any limits 'that may be selected by 'the user of the iron,but under no circumstances will operation of the iron be permissible ata heat that may cause a tire if the current is not shut off after usingthe iron. lilith a very sensitive control device and 'the advantage ofleverage between said device and the switch it is possible to regulatethe action ot' the iron to a tine degree and such degree may be set bythe manufacturer so that the iron cannot be conveniently tampered withand its automatic safety feature destroyed.

It is thought that the operation and utility ofthe electric iron will beapparent without further description, and while in the drawing there isillustrated a preferred embodiment of my invention, it is to beunderstood that the structural elements are susceptible to suchvariations and modifications as fall within the scope of the appendedclaim.

ln an electrically heated iron having a cover under which is located anelectric switch and a thermostatic control device adapted to controlsaid switch and the heating of said iron ineans for supporting saidthermostatic control device and mechanism by which said switch may beactuated by said device, said means comprising a fourarm spider undersaid cover on which is mounted said thermostatic control device, abearing on one or' the arms of said spider at one side of saidthermostatic device, a lever pivotally supported by said` bearingbetween said spider and said cover and extending in the direction ofanother arm of said sp1der and articulated with said switch, saidthermostatic control device being at the juncture of said spider armsand having a portion thereof 'attached to said spider, and means carriedby said lever opposite the attached ortion of said control device andextending through said cover adapted for adjustment to regulate theoperation of said lever by said thermostatic control device.

In testimony whereof I alix my signature.

JAMES N. LEWIS.

